Insight into strontium recovery from oilfield water by porous fiber-supported ammoniated titanium phosphate: Adsorption performance and mechanisms

There are abundant strontium resources in oilfield water with vast economic potential, but they have not yet been explored due to the complex matrix composition and the lack of cost-effective extraction technologies. Herein, four kinds of α -type ammoniated phosphates (A-MPs, M(NH 4 PO 4 ) x (HPO 4 ) 2- x ; M = Zr, W, Mo, and Ti, 0 ≤  x  ≤ 2) were designed and compared based on Density Functional Theory (DFT) calculations. It was inferred that ammoniated titanium phosphate (A-TiP) has both high structural stability and superior Sr 2+ adsorption performance due to its low formation energy and Sr 2+ adsorption energy. This conclusion was confirmed by the synthesis of A-TiP through a simple solid-state synthesis, and the maximum adsorption capacity of the optimized A-TiP was 320.9 mg·g −1 . To facilitate the industrial application of powdery A-TiP, it was further fabricated into fibers by wet spinning technology with low-cost PVC as the binder. Since the mesoporous structure and high stability of the obtained adsorbent (PVC-A-TiP), it still exhibited a high maximum adsorption capacity ( q max  = 291.75 mg·g −1 ), strong adaptability (active pH = 4 ∼ 12), and a short adsorption equilibrium time ( t e  = 60 min). When applied for Sr 2+ recovery from complex oilfield water, the distribution coefficient of Sr 2+ reached 11740.21 mL·g −1 , and the dynamic adsorption capacities ranged from 121.61 to 162.46 mg·g −1 . The material also showed excellent cycle stability, and the adsorption performance did not decrease even after 50 adsorption-desorption cycles. These excellent results demonstrate that the developed material can be employed as a potential adsorbent for selective extraction of Sr 2+ from oilfield water or other liquid Sr minerals.